my post configuration questions

I've done almost everything I wanted to, including a minor migration from office live. However, in a week I've got the big migration, (I should say important, not all that big) and after which I'll of course be in full production... and I really could use a little assistance from my senior administrators before hand to help me understand first of all some minor issues that remain unresolved as well as a few questions.

1. Non zimbra network services -
I currently have everything else turned off except an http server for my R1 backup server which listens on 8080. Ist, if I actually wanted to, could I easily run exim and dove on no-conflicting ports? The only reason I might would be if we're tight on zimbra licenses. However, (and I must apologize, I think I might find the answer to this on my own..but it's been a long week) I'm pretty sure I can use zimbra for this... and if so, am i right in my understanding that it does not count against my licenses? I'm going to need port 80 shortly on my prod server. For a couple days I did run my standard apache server on port 80, and moved zimbras ports from 80 and 443 and things seemed to work fine... however, one night around 4 in the morning I was poking around some logs and saw some errors which as best as I can recall were port 80 conflict errors. I turned of my default apache and put everything back like it was post install. When I have to once again have that server listen on port 80, I'd like to be sure I haven't missed anything. While I'm certain all of the information for this exists I have not found what I would call a definitive reference, in fact this has been discussed... sometimes heatedly in the forums. Is there in fact such a reference on one place, or could someone give me a list what needs to be moved, or more importantly, tell me what is expecting to find httpd listening on 80 and 443, that I am unaware of? What is the accepted method for this?

2. Mysql -
I have fairly well defined methodologies regarding database configuration and optimization, but not with Apache Lucene, and I don't have a frame of reference for system resource consumption or other metrics for this environment. Long time ago I administered large Sendmail servers.... ha So... I'd be interested in hearing about any capacity planning models being used. Within a week I'll have just under 50 users located in several states who will use the system continuously and will suck down whatever disk space is available about twice as fast as expected. Lots of attachments which average over 2 MB, and a new wrinkle for all concerned, I've set up a series of nested briefcase folders for managing and archiving production logs. I'm planning on rolling off this document store to another volume periodically via HSM, and then archiving it with R1 cdp.

These guys are actually acquiring a competitor, 1 branch location at a time, which will put it at over 100 with in about 6 months. We did their in house software which we manage, so we're able to share some resources. We could go beyond these numbers, but this is the level I want to plan for.

We have a new 2620 dual sandy hex cores, although only with SATAs... They'll be some additional load at first, but I'm thinking we're in pretty good shape.